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Biologists investigate mysterious sun star beach stranding

Dozens washed ashore at Sunshine Cove

This April 30 photograph provided by NOAA Fisheries shows one of the multi-armed sea stars, known as Sunflower stars or sun stars, that was stranded at Sunshine Cove and then examined by a local biologist at the Auke Bay Laboratories. Biologists investigated the sea star stranding and concluded they did not show symptoms of sea star wasting disease.

This April 30 photograph provided by NOAA Fisheries shows one of the multi-armed sea stars, known as Sunflower stars or sun stars, that was stranded at Sunshine Cove and then examined by a local biologist at the Auke Bay Laboratories. Biologists concluded the subtidal creatures did not show symptoms of sea star wasting disease.

This April 29 photograph provided by NOAA Fisheries shows some of the multi-armed sea stars, known as Sunflower stars or sun stars, that washed up on the shore at Sunshine Cove in Juneau. Biologists investigated the stranding and concluded they did not show symptoms of sea star wasting disease.

Some stars burn out. Others just fade away. And some mysteriously get stuck on the beach.

Two dozen colorful starfish recently washed ashore at Sunshine Cove and became stranded on a storm berm high up on the beach. The unusual mass stranding of the Pycnopodia helianthoides, known as Sunflower stars or sun stars for their multiple arms, prompted local biologists to investigate if it was a casualty of sea star wasting syndrome, which has ravaged the West Coast by causing massive declines in the starfish population.

Wasting syndrome probably wasn’t to blame in this case, concluded Mandy Lindeberg, a NOAA fisheries research biologist who examined the starfish.

“There was definitely something wrong with them,” Lindeberg told the Empire, adding the invertebrates were found in a weakened state, “but it was not associated with the wasting disease.”

Lindeberg had examined one of the creatures at her office at the Auke Bay Laboratories on April 30, a day after they were collected at the beach by staff. An anonymous caller in Juneau reported the stranding to NOAA.

The Sunflower star Lindeberg observed had 17 arms, was “as big as a dinner plate,” purplish in hue and oozing with water — but it did not have any of the symptoms associated with wasting, she said.

“If they really are diseased, it’s blatantly obvious,” Lindeberg said, noting lesions form on their skin, arms fall off and death follows within three or four days.

She sent pictures of the specimen to another researcher at the University of California, Santa Cruz, which runs a national wasting syndrome monitoring program and database, just to be sure. That researcher, field biologist Melissa Miner, confirmed they did not appear to have symptoms.

While starfish have been wasting in massive numbers on the West Coast — from Mexico to California, Oregon and Washington — Alaska seems largely immune. There have only been three confirmed instances of wasting here, all reported last summer: one offshore of Kayak Island near Sitka, and at two locations in captivity, the Sitka Sound Science Center aquarium and the Anchorage Museum aquarium.

None of those confirmations were at the wide-level scale that has been documented in California and elsewhere, Miner told the Empire.

“We’re only confident that it’s wasting syndrome when massive numbers of sea stars die,” she said by phone from Bellingham, Wash., where she works remotely. “That wasn’t the case in Sitka. We saw some individuals that looked like what could have been sea star wasting syndrome.”

Not much is known about sea star wasting syndrome, including its cause. Scientists don’t know whether it’s caused by an infection, virus, bacteria, or something else. It’s been around for decades, though, with the earliest confirmation in 1970 in southern California.

Reports of wasting surfaced again last summer. This time, however, it spread farther than scientists have ever seen, and in record numbers, Miner said.

“It could be as high as a million,” she said. “It’s definitely in the hundreds of thousands.”

Before, the northernmost confirmation was Monterey Bay in central California. Now, Sitka is the northern most confirmation in the wild. The southernmost confirmation is the Coronado Islands in Mexico. The wasting seems to be everywhere in between, according to a sea star wasting map on the UC Santa Cruz website put together by Pacific Rocky Intertidal Monitoring, a partnership of environmental agencies.

Historically, the biggest wasting events tend to correlate with El Niño, or warm ocean water temperatures, which makes this event different, Miner said.

“This particular event isn’t coupled with a major warm water event like we’ve seen historically,” she said. “There does seem to be a temperature factor.”

Perhaps Alaska’s cold water is the reason it hasn’t seen as much wasting as other states, she mused.

“But we really don’t know,” she added. “That’s a guess.”

As for the stranding at Sunshine Cove, the best Miner and Lindeberg could do is speculate as to why the Sunflower stars were perched up on the storm berm.

“A storm could have tossed them up there or they were already weak and could not swim out with the rapidly retreating tide,” Lindeberg guessed, adding that maybe they were weakened from spawning. “They do spawn this time of year and put a lot of their energy into reproduction.”

Miner said maybe they just got trapped somewhere they shouldn’t be. It’s also possible someone placed them there, she said.

“It might have just been somebody doing something not very nice,” she said.